As a species, we have been sleeping alongside our four-legged friends since … well, no one is entirely sure, but certainly long before modern bedtime routines emerged. The first real beds appeared about 4,000 years ago, while the domestication of dogs began at least 20,000 years before that, with our canine companions working as a combination of predator deterrent and hot‑water bottle.
These days, there are very few roaming wolves, and we have duvets and heated blankets to keep us warm. So, is it possible that letting dogs – or cats – share our sleeping space is doing us more harm than good?
The short answer is: probably not. “I don’t think there’s anything to worry about,” says Esme Wheeler, a dog welfare expert at the RSCPA who – in the interest of full disclosure – lets her dog sleep on the bed. “There might be some tiny risks in terms of disease transmission, or fleas, but if you’re living with a dog anyway, having it in the bed isn’t going to increase the risk of that.
“If you’re a light sleeper, it might be a little bit disruptive to your sleep, as dogs have different sleep patterns from humans – they can be hyperalert, so they’re listening out for things and sometimes they will get up suddenly, which can be a problem.”
How problematic is this sort of sleep disruption? Perhaps surprisingly, there isn’t enough research to make strong recommendations, and the results of studies are mixed.
One national survey of Australians found that dog and cat owners were generally less likely to be on medication for sleeping difficulties than non-owners – although the survey didn’t ask specific questions about co-sleeping and the direction of causality is not clear. A more recent study, which used accelerometers to measure sleep quality in humans and their co-sleeping canines, found that, although having a dog in the room had little effect on sleep, an animal on the bed led to decreased sleep efficiency for its owners.
In other surveys, some pet owners reported that their pets were disruptive, while others described them as being beneficial. Overall, inconclusive. But if you are not noticing the effects on a daily basis, then you probably don’t have much to worry about.
But what about the dogs? This is where things get a bit trickier, as our faithful pets find it difficult to understand when sleeping arrangements change, or why.
“The thing to be aware of is consistency,” says Wheeler. “If you start letting your dog sleep on the bed, you can’t expect it to understand when it’s suddenly not allowed to any more. If you’re going to do it, you either need to do it and continue it or teach the dog that they can come on to the bed at certain times – perhaps there’s a stimulus that represents that, such as a special blanket.” This can be especially important if your relationship status changes – if a partner vetoes your canine co-sleeping arrangements, you will need to gently retrain your dog.
It is worth noting that, as your dog ages, it may become less able to get up or down from the bed. To reduce stress in later years, it is a good idea for them to have their own sleeping space.
It is important to remember that dogs and children should not be left alone together in sleeping spaces. “No matter how used to dogs a child is – and vice versa – it is essential for an adult to be actively involved and closely supervising at all times when they are together,” says the Dogs Trust.
And what about cats? There aren’t as many studies here, as co-sleeping felines tend to be less common. “Cats have had a shorter domestication journey than dogs,” says Wheeler. “Dogs have co-evolved with humans and some people would say they have domesticated us as much as we have them. That is not to say that cats are not capable of forming close attachments to humans, of course.” Still, most of the advice above still seems to apply – and cats, like dogs, can reduce the stress hormone cortisol. Reptiles, though? It’s a strong no.